I need to get a new tranny for the 71 Chevelle. I currently have a th350. I wanted to go to manual for the .50 overdrive, but have recently decided to stay with the auto for consistency and cost. I had budgeted about $3500 for the swap so now I have this to put into an auto. The main goal is to have overdrive and second I don't want to have to replace the transmission when I put a blower on the 383 in process. So it needs to handle around 800+ hp. What do you all recommend? I've looked at 2004r, 700r4, 4l80e and th400 w/ gearvendors unit. I like the idea of having a lock up convertor for highway crusing so I can run a big stall. Is a 4l80e a lock up trans? I was looking at this one here: http://www.transmissioncenter.net/4L80E.htm let me know what you think. What would the conversion be like to install this? I need to decide soon. I want to have it installed within the next two months, but I have not made a final decision yet so all recommendations would be greatfuly appreciated.

My 2004R seems to be surviving well behind the 600+ HP/TQ put out by the "502". The only problem in 3 years has been throwing the spring off the governor once and that includes about 100 runs down the 1320.

What is your weight and expected use? What do you have in the rear to take that kind of power? Is the car caged?

If you are looking for street use you won't be in 800 HP mode often and you will be traction limited so a properly built (read billet parts) 2004R would probably work. At 800+ HP you will break a lot of things. A 700R4 will not come close to surviving. The gearvendor unit and the 4L80E both use a lot more HP than the 2004R.

For that big of a budget, how about a stout 400 Turbo with a GearVendor's behind it? I think the GV goes for about $2400. Then (depending on the local pricing or whereever you want to spend your money) that would leave $750 for the 400TH and $350 for a decent converter.

I'm not sure about all the other "incidentals", such as driveshaft work, flywheel, dipstick and tube, flywheel cover, etc. Part of which you may or may not need.

Just a thought. I'd think you'd just about be bulletproof at that point.

I was trying to stay away from the th400 because I want a lock up convertor, so I can go for some long distance runs like the power tour.